Tear open pouch

ABSTRACT

A pouch for containing a flowable material manufactured in a vertical form, fill and seal process wherein a pouch is formed from a sheet of thermoplastic film and a transverse heat seal formed between pouches as they are filled serves as a top closure for a lower pouch and a bottom closure for an upper pouch, wherein the pouch is provided with an easy open feature just above or below a respective closure, which comprises a second seal formed between two layers of film in a portion of an edge of the pouch that is in close proximity to and extends inwardly from a corner of the pouch to provide a tear line to open the pouch, and process for manufacturing.

FIELD OF THE INVENTION

The present invention relates to a pouch for containing flowablematerials which is easy to tear open, a heat sealing assembly for avertical form, fill and seal machine for use in manufacturing the pouch,and a process for manufacturing the pouch.

BACKGROUND OF THE INVENTION

Packaging pouches are typically made on vertical form, fill and sealmachines. Using such a machine, a flat web of synthetic thermoplasticfilm is unwound from a roll and formed into a continuous tube in a tubeforming operation, by sealing the longitudinal edges of the filmtogether to form a lap seal or a fin seal. The tube thus formed ispulled vertically downwards to a filling station. The tube is thencollapsed across a transverse cross-section of the tube, the position ofthe cross-section being at a sealing device below the filling station. Atransverse heat seal is made by the sealing device at the collapsedportion of the tube, thus making an airtight seal across the tube. Thesealing device generally comprises a pair of jaws. After making thetransverse seal, but before the jaws of the sealing device are opened, aquantity of material to be packaged, for example a liquid is caused toenter the tube at the filling station, and to fill the tube upwardlyfrom the aforementioned transverse seal. The tube is then caused to movedownwardly a predetermined distance. This movement may be under theinfluence of the weight of the material in the tube, or it may be causedby pulling or mechanically driving the tube. The jaws of the sealingdevice are closed again, thus collapsing the tube at a second transversesection. The second transverse section may be above, usually just abovethe air/material interface in the tube, or the second transverse sectionmay be below the air/material interface. The sealing device seals andsevers the tube transversely at the second transverse section. Thematerial filled portion of the tube is now in the form of a pillowshaped pouch. Thus the sealing device has sealed the top of the filledpouch and sealed the bottom of the next to be formed pouch, all in oneoperation. The filling of the product may be conducted on a continuousor intermittent basis. One such vertical form, fill and seal machine ofthe type described above is sold under the trade-mark PREPAC. Othersuitable machines are sold under the trade-marks INPACO and ELECSTER.

There are other types of machines wherein the sealing device does notsever the tube at the second transverse section, but does sever the tubesubsequently. In order to package certain flowable but viscousmaterials, it is often desirable to heat the material. When such is thecase, the packaging process is often referred to as a hot-fill process.

A variety of flowable materials may be packaged in this manner, forexample, milk, syrups, sauces, juices, water and the like. The term“flowable material” is meant to encompass materials which are flowableunder gravity or may be pumped. Such materials may include emulsions,pastes, peanut butter, preserves, dough, ground meat, powders,detergents, oils and granular solids. It is anticipated that this pouchcould be used for containing flowable materials, in particular foodsthat are packaged under sterile, pasteurized or aseptic conditions.

The pouches produced through this type of process can be manufactured tocontain any volume of flowable material. In the situation where drinkingfluids are packaged in this fashion, a typical size might be 250 mls or500 mls. In such instance, it is possible to consume the fluid directlyfrom the pouch. Thus, providing a pouch that includes an easy tearopening for this purpose is desirable since it avoids the necessity touse an implement such as a knife or scissors. In addition, because thesepackages are meant to be one-time use packages it is appropriate thatthe manner in which they are manufactured is as economical as possible,without sacrificing the basic packaging requirements for the materialsin question.

There are many advantages to the present invention such as theeconomical single step manufacturing process, and the lack of anyrequirement for a cutting device of any sort, either in manufacturing oropening the pouch.

Many solutions have been proposed for producing packages of this type,and typically such packages have included a notch or tear line whichallows the package to be opened. Examples of the solutions offeredincluded those found in U.S. Pat. No. 3,759,439 issued Sep. 18, 1973 toCross, et al., U.S. Pat. No. 4,176,567 issued Dec. 4, 1979 to Weisberg,U.S. Pat. No. 4,890,744 issued Jan. 2, 1990 to Lane, Jr., et al. andU.S. Pat. No. 5,470,419 issued Nov. 28, 1995 to Sasaki, et al. Thesestructures typically involve providing a notch or tear line in thesealed area of the pouch or by other means, such as that found in U.S.Pat. No. 5,470,419 which provides strings in the plastic film when it ismade by melt extrusion. Another solution is found in U.S. Pat. No.4,176,567, wherein a sealed marginal portion of a flat bag is puncturedby a uniquely shaped tool head having a faceted tapered tool head. Thefaceted tapered tool head is provided with preferably three and, in anyevent, not many facets producing a corresponding number of straight,longitudinally extending, bag-cutting edges converging to a bagpuncturing point at the end of the tool head. Thus, the process hererequires an additional step after the bag has been manufactured and thecontents sealed, as well as the use of the tool that is meant topuncture the sealed area of the bag. Another example is found in thepreviously referenced U.S. Pat. No. 3,759,439 which includes a flexiblereinforcement having a highly localized line of weakness, thereinforcement being bonded to the surface of the film or incorporatedpartly or wholly within its thickness. Again a complicated solution thatwould seem to involve additional costs in the manufacture of thepackaged product.

Reference may also be had to U.S. Pat. No. 5,038,550 which describessealing the edge of a pouch with a semicircular heat seal with a slittherein. See FIG. 11 of this patent. The slit in this case is cut intothe edge of the pouch and has an isolating seal closely around it, andthen a contoured seal further out.

Thus there is a need to produce an easy open pouch for packagingpurposes that is simple in design and, easy and economical tomanufacture.

SUMMARY OF THE INVENTION

The present invention seeks to provide a pouch that can be easily tornopen which can be manufactured using a vertical form, fill sealapparatus which permits the formation of a tear line simultaneously withthe sealing of the pouch.

Thus the present invention provides in one aspect a pouch for containinga flowable material manufactured in a vertical form, fill and sealprocess wherein a pouch is formed from a sheet of thermoplastic film anda transverse heat seal formed between pouches as they are filled servesas a top closure for a lower pouch and a bottom closure for an upperpouch, wherein the pouch is provided with an easy open feature justabove or below a respective closure, which comprises a second sealformed between two layers of film in a portion of an edge of the pouchthat is in close proximity to and extends inwardly from a corner of thepouch to provide a tear line to open the pouch.

In another aspect, the invention provides a heat sealing assembly foruse in a vertical form, fill and seal apparatus for sealing at least twolayers of thermoplastic film together, comprising a first jaw and asecond jaw, a first and a second electrical impulse heat sealing elementmounted on the first jaw, at least one of said jaws being capable oftransverse motion and adapted to collapse a tubular film made from saidthermoplastic film and to allow the film to pass between said jaws, thefirst electrical impulse heat sealing element being about the length ofthe width of the collapsed tubular film so that the flattened tube canbe sealed and cut, and the second electrical impulse heat sealingelement mounted on the first jaw being in close proximity to the firstelement and arranged so that the seal it creates extends from one edgeof the collapsed tube for a short distance towards the interior of thetube so that a second seal can be made in the tube to provide a tearline for opening the pouch.

In yet another aspect, the invention provides a process formanufacturing a pouch for containing a flowable material which comprisesforming a thermoplastic film into a film tube by forming a vertical finseal or lap seal in the tube, drawing the tube through a heat sealingassembly of a vertical form, fill and seal apparatus, collapsing thetube, forming a first transverse seal in the tube, continuously fillingthe tube with a flowable material, allowing the filled tube to drop downa predetermined distance from the heat sealing assembly, collapsing thefilled tube and heat sealing the tube again with the heat sealingassembly to provide a first seal across the tube and a simultaneous cuttherethrough so that a pillow shaped pouch is formed, a second sealbeing provided simultaneously by the heat sealing assembly, which is inclose proximity to the top seal of the pouch and extends inwardly fromthe adjacent side edge of the pouch, thereby providing a tear line foropening the pouch.

In another aspect there is provided a heat sealing assembly for use in avertical form, fill and seal apparatus for making flowable materialfilled pouches, the assembly being adapted for sealing a thermoplasticfilm together to form a tube which is filled with the flowable materialand sealed and cut into pouches containing such material, which assemblycomprises a transversely oriented jaw and a vertically oriented jaw, thevertically oriented jaw being adapted to seal edges of the film with afin seal or an overlap seal, the horizontal jaw being adapted fortransverse motion and to collapse the tubular film and to allow thetubular film when filled with flowable material to pass between itsmembers, which cut and seal the tubular film to form pouches, thevertically oriented jaw having an electrical impulse heat sealingelement arranged vertically in a member thereof and being about thelength of a pouch, the transversely oriented jaw having an electricalimpulse heat sealing and cutting element and being about the width of apouch, so as to cut and seal the collapsed and filled tubular film,whereby the seal formed provides a bottom closure for an upper pouch anda top closure for a bottom pouch, and providing at least one tear linefor opening the pouch by providing at least one of the members of atleast one of the jaws with a second electrical impulse sealing elementarranged in the member so that at least one second seal issimultaneously formed that extends from one edge of the pouch and for ashort distance towards the interior of the pouch to form the at leastone tear line or an additional sealing jaw is provided which actssimultaneously with the transverse or vertical jaw to provide the atleast one tear line.

The second seal formed in the pouch may take any suitable shape such ascurved or straight, although a straight line is illustrated in theexample of this invention produced. Obviously, a shape that directs thetear so that a corner of the pouch is removed would be most desirable.The angle of this second seal relative to the first seal may be variedin a suitable manner. Thus, the two seals may be spaced and parallel, orthe second seal may extend from the outer edge towards the sealed edge.

It is also possible to form a second seal in the vertical seal. Forexample, a satellite sealing mechanism can be associated with thevertical seal jaws in somewhat the same manner as the above embodimentis associated with the horizontal jaw. A short auxiliary seal can beformed in the machine direction at the opposite side of the pouch to thevertical fin seal. This short seal would be in the horizontal jaw areaso that it would be cut in two by the horizontal seal. An easy tearnotch would be created in the pouch above and below the horizontal seal.Thus each pouch would have two tear off notches.

Other locations for the second seal are possible as long as a suitabletear is produced that opens the pouch in a manner that allows thecontents to be dispensed or consumed. The corner being removedrepresents an example of a suitable result.

Pouch Film

Many types of films can be used to manufacture the pouches of thepresent invention. Generally these films must be capable of self-sealingand processing through the vertical form, fill and seal equipment. Theyshould be stiff enough and strong enough for the proposed packagingapplications. The nature of the packaging application determines thefilm selection and the person skilled in the art would be capable ofreadily selecting a suitable film for the desired purpose. Examples ofsuitable films include any synthetic thermoplastic polymeric film whichmeets the above-mentioned criteria. For example, PCT Application WO99/06476 discloses polymer films made from a homogeneously branchedlinear ethylene interpolymer film which may be a two-layer or athree-layer coextruded film containing at least one seal layer of ahomogeneously branched linear polyethylene. In PCT Application WO98/50230 there is described a heat sealable multilayer film comprisingabout 10% by volume of the overall film structure made from anethylene-styrene copolymer obtained using a single-site catalystpolymerization process and one or more layers comprising:

at least one interpolymer selected from interpolymers of ethylene andone or more C₃-C₂₀ α-olefins made by polymerization processes usingsingle-site catalyst, non single-site catalyst and mixtures of suchcatalysts, and blends thereof. The films may contain a barrier layerselected from nylon polymers, polyethylene terephthalate polymers,amorphous nylon or ethylene vinyl alcohol. An additional tie layer maybe present and can be selected from ethylene vinyl acetate polymer,ethylene acid copolymers, ionomers or anhydride functionalized ethylenecopolymers. And all of these may be combined with at least one highpressure ethylene homopolymer. Other examples of suitable films aredescribed in the following additional references: WO 98/34844, WO98/29249, WO 97/20693, WO 97/12755, WO 95/21743, WO 95/10566, WO95/00587, the disclosures of which are incorporated herein by reference.These are merely representative examples of thermoplastic films and theinvention is not to be limited in any way with respect to the filmselected for manufacture of the pouch of the invention.

The heat-sealing assembly of the invention is for use on vertical form,fill, seal machines. Examples of how the assembly is mounted in such amachine may be found in EP 0573447B1, US 2001/10032710A1 and U.S. Pat.No. 5,538,590, the disclosures of which are incorporated herein byreference. A variety of these machines are known to be commerciallyavailable and included, but not limited to, are machines manufacturedand sold by Prepac, Thimmonier, Inpaco and Elecster. An early patentgranted to Prepac for such a machine is U.S. Pat. No. 3,886,714, thedisclosures of which are incorporated herein by reference. The heat sealassembly can be mounted in the standard jaws of the vertical form, fill,seal apparatus in a manner as would be apparent to a person skilled inthe art.

The process of the invention is well known except for the aspectprovided by the second seal described above which offers an easy openfeature for a filled pouch.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which are used to illustrate the presentinvention, a typical embodiment of the present invention is described.The invention is not to be limited to this embodiment as the embodimentis included for purposes of illustration only.

FIG. 1 illustrates the components of a heat seal assembly for a verticalform, fill and seal machine according to the present invention, whichallows for an arrangement that provides an auxiliary seal in the generaldirection transverse to machine direction;

FIG. 2 illustrates the same components found in FIG. 1 from the oppositedirection;

FIG. 3 illustrates a series of pouches of the present invention made onthe arrangement of FIGS. 1 and 2, which demonstrate the tear openfeature;

FIG. 4 is a schematic perspective view of an arrangement thatillustrates another embodiment of the invention wherein a second sealcan be created in the machine direction of a pouch;

FIG. 5 illustrates a pouch made on the arrangement of FIG. 4; and

FIGS. 6 and 7 illustrate two alternative positions of a second seal on apouch which seal is created in the machine direction.

DETAILED DESCRIPTION OF THE INVENTION

Referring first to FIG. 1, there are shown the components of a heatsealing element of the present invention. The element is shown generallyat 10. The element 10 comprises a backup support 11, a backup rubber 17and a main sealing element 18. In FIG. 1, first and second seal reliefs13 and 14, respectively, can be seen. In this form of the invention, theseals 13 and 14 are parallel one to the other, although the second shortseal 14 can take other shapes and directions as described earlier. Themain element 18 includes heating element 12.

Referring now to FIG. 2, one can see the opposite view of the sealingelement assembly to that of FIG. 1. Thus on the main element 18, thefirst and second seal impressions which are created in the pouches asthey are sealed in the process of manufacture are clearly shown at 15and 16. When the heat seal assembly is installed in a vertical form,fill, seal machine, the backup rubber 17 and backup support 11 arelocated on one jaw while the main element containing the heating elementis located on the other jaw.

Referring now to FIG. 3, a pouch 20 manufactured according to theprocess of the present invention is illustrated. The top seal 22 andbottom seal 25 can be seen as well as the vertical seal 23. The secondseal is clearly shown in the top pouch of the Figure and the three otherpouches in descending order illustrate the tearing of corner 24 of thepouch to create an opening 24 a in the pouch for dispensing or accessingthe packaged contents.

Referring now to FIG. 4, there is illustrated schematically a fill tube30 inside a film tube 31 which is meant to be fin sealed at its sideedge 33. Sealing bar 32 which represents a portion of a sealing device(not shown), is arranged in the machine direction or vertical directionand is meant to be provided with two sealing elements 15 and 16 as seenin the heat sealing element 18 shown in FIG. 2.

FIG. 5 illustrates a pouch shown generally at 40 made using thearrangement of FIG. 4. Pouch 40 is made from a film tube 41 which isformed by making a fin, side or vertical side seal 43. A short seal 42is formed in the pouch 40, adjacent seal 43. In this case, seal 42 isshown to be spaced from and parallel to seal 43. It should be noted thatsealing bar 32 may be formed and positioned such that the short seal 42is formed in pouch 40 so that it extends through two pouches 40. In suchinstance, each pouch 40 would have a short seal 42 at either transverseedge 44 and hence could be torn open using either seal 42.

FIGS. 6 and 7 illustrate pouches shown generally at 40, with likenumerals identifying like elements. The pouch of FIG. 6 shows a singlesecond seal 42 made by a satellite second sealing element (not shown)that is made in edge 45 which is opposite a fin seal 43 formed in pouch40. The second seal 42 may be formed at the top and bottom edges (44) ofpouch 40, depending on how the satellite second sealing element ispositioned.

The invention may be varied in any number of ways as would be apparentto a person skilled in the art and all obvious equivalents and the likeare meant to fall within the scope of this description and claims. Thedescription is meant to serve as a guide to interpret the claims and notto limit them unnecessarily.

1. A pouch for containing a flowable material manufactured in a verticalform, fill and seal process wherein a pouch is formed from a sheet ofthermoplastic film and a transverse heat seal formed between pouches asthey are filled serves as a top closure for a lower pouch and a bottomclosure for an upper pouch, wherein the pouch is provided with an easyopen feature just above or below a respective closure, which comprises asecond seal formed between two layers of film in a portion of an edge ofthe pouch that is in close proximity to and extends inwardly from acorner of the pouch to provide a tear line to open the pouch.
 2. A heatsealing assembly for use in a vertical form, fill and seal apparatus forsealing at least two layers of thermoplastic film together, comprising afirst jaw and a second jaw, a first and a second electrical impulse heatsealing element mounted on the first jaw, at least one of said jawsbeing capable of transverse motion and adapted to collapse a tubularfilm made from said thermoplastic film and to allow the film to passbetween said jaws, the first electrical impulse heat sealing elementbeing about the length of the width of the collapsed tubular film sothat the flattened tube can be sealed and cut, and the second electricalimpulse heat sealing element mounted on the first jaw being in closeproximity to the first element and arranged so that the seal it createsextends from one edge of the collapsed tube for a short distance towardsthe interior of the tube so that a second seal can be made in the tubeto provide a tear line for opening the pouch.
 3. A process formanufacturing a pouch for containing a flowable material which comprisesforming a thermoplastic film into a film tube by forming a vertical finseal or lap seal in the tube, drawing the tube through a heat sealingassembly of a vertical form, fill and seal apparatus, collapsing thetube, forming a first transverse seal in the tube, continuously fillingthe tube with a flowable material, allowing the filled tube to drop downa predetermined distance from the heat sealing assembly, collapsing thefilled tube and heat sealing the tube again with the heat sealingassembly to provide a first seal across the tube and a simultaneous cuttherethrough so that a pillow shaped pouch is formed, a second sealbeing provided simultaneously by the heat sealing assembly, which is inclose proximity to the top seal of the pouch and extends inwardly fromthe adjacent side edge of the pouch, thereby providing a tear line foropening the pouch.
 4. A heat sealing assembly for use in a verticalform, fill and seal apparatus for making flowable material filledpouches, the assembly being adapted for sealing a thermoplastic filmtogether to form a tube which is filled with the flowable material andsealed and cut into pouches containing such material, which assemblycomprises a transversely oriented jaw and a vertically oriented jaw, thevertically oriented jaw being adapted to seal edges of the film with afin seal or an overlap seal, the horizontal jaw being adapted fortransverse motion and to collapse the tubular film and to allow thetubular film when filled with flowable material to pass between itsmembers, which cut and seal the tubular film to form pouches, thevertically oriented jaw having an electrical impulse heat sealingelement arranged vertically in a member thereof and being about thelength of a pouch, the transversely oriented jaw having an electricalimpulse heat sealing and cutting element and being about the width of apouch, so as to cut and seal the collapsed and filled tubular film,whereby the seal formed provides a bottom closure for an upper pouch anda top closure for a bottom pouch, and providing at least one tear linefor opening the pouch by providing at least one of the members of atleast one of the jaws with a second electrical impulse sealing elementarranged in the member so that at least one second seal issimultaneously formed that extends from one edge of the pouch and for ashort distance towards the interior of the pouch to form the at leastone tear line or an additional sealing jaw is provided which actssimultaneously with the transverse or vertical jaw to provide the atleast one tear line.